JP2003124911A - Optical communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of light-source components without limiting the number of wavelength that can be utilized by a remote node. SOLUTION: A center node 201 has a multiwavelength light source 231 that generates output light where a plurality of light carriers having different wavelength are subjected to wavelength multiplexing, and an optical coupler 232 that distributes the output light from the multiwavelength light source 231 for sending to a plurality of light transmission and reception sections 2111 to 211m of the center node 201 and a optical fiber transmission line connected to an adjacent remote node. Remote nodes 2021 to 202m have optical couplers 2331 to 233m that distribute the output light sent from the center node 201 or the adjacent remote node for sending to light transmission and reception sections 2121 to 212m of the remote node and the optical fiber transmission line connected to the adjacent remote node.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication system, and more particularly to an optical communication system for transmitting a plurality of independent optical signals having different wavelengths.

[0002]

2. Description of the Related Art In recent years, along with the progress of multimedia services represented by the Internet, it is necessary to increase the information transfer capacity in an optical network that constitutes the backbone of the network. As a technique for increasing the information transfer capacity, an optical wavelength multiplex transmission technique for transmitting a plurality of independent optical signals having different wavelengths to one optical fiber has been put to practical use.

FIG. 1 shows the configuration of a conventional optical network. The optical network is composed of at least one center node 101 and m (m is a natural number) remote nodes 102 _{1 to} 102 _m . The optical transmission device ₁₁₁ 1 - 111 _m of the center node 101, each of the remote node ₁₀₂ 1 to 102 _m of the optical transmission device 112
It is connected to _{1 to} 112 _m with two optical fiber cables, and carries out large-capacity communication by optical wavelength multiplex transmission technology.

Optical transmission devices 111 _{1 to} 111 _m , 112 ₁
-112 _m is a plurality of light sources 121 _{1 to} 12 having wavelengths ₁ to n.
1 _n , optical modulators 122 _{1 to} 122 _n that modulate the optical signals output from the respective light sources, and a multiplexer 123 that multiplexes the outputs of the respective optical modulators. .
Further, the optical transmission devices 111 _{1 to} 111 _m and 112 _{1 to} 11
2 _m is a demultiplexer 124 for demultiplexing the wavelength-multiplexed optical signal
And an optical receiver 125 for demodulating each of the demultiplexed optical signals.
_{1 to} 125 _n .

With such a configuration, the transmitting unit outputs the outputs of the light sources 121 _{1 to} 121 _n to the optical modulators 122 ₁ to 121 _n.
A plurality of independent optical signals modulated by 22 _n are combined into a multiplexer 12
A wavelength-division-multiplexed optical signal is wavelength-division-multiplexed on one optical fiber by the transmission line 3. The receiving unit demultiplexes the received wavelength-multiplexed optical signal into a plurality of wavelengths by the demultiplexer 124, and the optical receivers 125 _{1 to} 125 _n receive the respective signals. The transmitting unit and the receiving unit face each other and communicate with each other.

[0006]

However, in such an optical network, it is necessary to dispose a plurality of independent light sources having different wavelengths in each optical transmission device, which increases the number of light source parts, and The cost of the transmission device increases. Further, there is a problem in that each optical transmission device requires a wavelength monitoring function and a wavelength stabilization function, and monitoring control of the optical transmission device in each node becomes complicated.

In order to solve this problem, a method of constructing a link network in which a WDM optical carrier is distributed from a center node to each remote node and each remote node performs only modulation is disclosed in Japanese Unexamined Patent Publication No. 8-18538 and JP-A-7-
It is disclosed in Japanese Patent No. 231,305. According to this configuration method, one wavelength is assigned to each remote node, and the assigned wavelength is modulated by each remote node and transmitted to the center node.

Therefore, in the link network according to this configuration method, each wavelength-multiplexed optical carrier distributed from the center node is in the form of transmitting one optical signal, and the total number of wavelengths that can be used by all remote nodes. There is a limitation that the number of wavelengths is less than or equal to the number of wavelengths of the wavelength division multiplexed optical carrier distributed from the center node.

The present invention has been made in view of the above problems, and an object thereof is to provide an optical communication system in which the number of light source components is reduced without limiting the number of wavelengths that can be used by a remote node. To do.

[0010]

In order to achieve such an object, the present invention provides a plurality of optical transmission / reception units of at least one center node and a plurality of optical transmission / reception units. In an optical communication system for performing communication by connecting at least one optical fiber transmission line to each of the optical transmission / reception units included in a remote node, the center node has an output light obtained by wavelength-multiplexing a plurality of optical carriers having different wavelengths. Generating a multi-wavelength light source and distributing the output light from the multi-wavelength light source, and sending the output light to an optical connector of an optical fiber transmission line connected to a remote node adjacent to the plurality of optical transceivers of the center node. An optical coupler, the remote node distributes the output light transmitted from the center node or an adjacent remote node, and the remote node An optical coupler for transmitting to the optical transceiver of the node and an optical connector of an optical fiber transmission line connected to an adjacent remote node, each of the optical transceivers being connected from the optical coupler connected to the optical transceiver. The communication is performed by inputting the output light, modulating each of a plurality of optical carriers wavelength-multiplexed with the output light, and sending the modulated optical carrier to the optical fiber transmission line.

According to a second aspect of the present invention, the optical transmission / reception unit of one center node and the optical transmission / reception unit of one remote node are connected by at least one optical fiber transmission line for communication. In the optical communication system, the center node distributes the output light from the multi-wavelength light source that generates output light in which a plurality of optical carriers having different wavelengths are wavelength-multiplexed, and outputs the light of the center node. An optical coupler for transmitting to the optical transceiver of the remote node via the optical fiber transmission line, each of the optical transceivers receiving the output light from the optical coupler and outputting the output light. It is characterized in that each of a plurality of optical carriers wavelength-multiplexed with light is modulated and sent out to the optical fiber transmission line to perform communication.

According to a third aspect of the present invention, the optical transmission / reception unit according to the first or second aspect receives the output light sent from the optical coupler, and demultiplexes it into a plurality of optical carriers. And a modulator that outputs an optical signal obtained by modulating each of the plurality of optical carriers demultiplexed by the demultiplexer with an electrical signal, and combines each of the optical signals output from the modulator. And a multiplexer for sending out to the optical fiber transmission line.

According to a fourth aspect of the present invention, one center node and a plurality of remote nodes are arranged in a ring shape,
An optical communication system for performing communication by connecting at least two optical fiber transmission lines to each of the plurality of optical transmission / reception units of the center node and each of the optical transmission / reception units of the plurality of remote nodes in a ring shape, The center node distributes the output light from the multi-wavelength light source that generates output light in which a plurality of optical carriers having different wavelengths are wavelength-multiplexed, and distributes the output light from the multi-wavelength light source, and the plurality of optical transceivers of the center node. An optical coupler for transmitting to an optical connector of an optical fiber transmission line connected to two adjacent remote nodes, the remote node distributing the output light transmitted from the center node or an adjacent remote node, Two optical couplers for sending one output to an optical connector of an optical fiber transmission line connected to an adjacent remote node, and the two optical couplers. An optical switch for selecting the other output of the optical coupler and connecting it to the optical transceiver of the remote node, each of the optical transceivers being the optical coupler or the optical switch connected to the optical transceiver. The communication is performed by inputting the output light from the above, modulating each of a plurality of optical carriers wavelength-multiplexed with the output light, and sending out the modulated optical carriers to the two optical fiber transmission lines.

According to a fifth aspect of the present invention, in the fourth aspect, the transmission section of the optical transmission / reception section inputs the output light transmitted from the optical coupler or the optical switch and divides the output light into a plurality of optical carriers. A wave demultiplexer, a modulator that outputs an optical signal obtained by modulating each of the plurality of optical carriers demultiplexed by the demultiplexer with an electric signal, and the optical signal output from the modulator It has a multiplexer that outputs a wavelength-multiplexed optical signal that multiplexes each, and an optical coupler that distributes the wavelength-multiplexed optical signal output from the multiplexer and sends it to the two optical fiber transmission lines. However, the receiving unit of the optical transceiver unit is
Optical switch for selecting the wavelength division multiplexed optical signal from the optical fiber transmission line of the book, a demultiplexer for inputting the wavelength division multiplexed optical signal from the optical switch and demultiplexing into a plurality of optical signals, and a demultiplexer for the demultiplexer A receiver that demodulates the waved optical signal and outputs an output electric signal.

According to a sixth aspect of the present invention, the optical transmission / reception unit according to the fourth aspect inputs the output light transmitted from the optical coupler or the optical switch and demultiplexes it into a plurality of optical carriers. A demultiplexer, a modulator that outputs an optical signal obtained by modulating each of the plurality of optical carriers demultiplexed by the demultiplexer with an input electric signal, and each of the optical signals output from the modulator Two transmitters each having a multiplexer that outputs a transmission signal obtained by multiplexing, and a distributor that distributes the input electric signal to each of the modulators included in the two transmitters,
A demultiplexer that inputs a wavelength-multiplexed optical signal from the optical fiber transmission line, demultiplexes the optical signal into a plurality of optical signals, and a receiver that demodulates the optical signal demultiplexed by the demultiplexer and outputs an output electric signal And a selector for selecting the output electric signal output by each of the two receiving units.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

[First Embodiment] FIG. 2 shows a first embodiment of the present invention.
2 shows a configuration of an optical network according to the exemplary embodiment. The optical network includes at least one center node 20.
1 and m (m is a natural number) remote nodes 202
It is composed of _{1 to} 202 _m . Center node 20
The optical transmission devices 211 _{1 to} 211 _m of the first optical transmission device 212 _{1 to} 211 _m of the respective remote nodes 202 _{1 to} 202 _m.
It is connected to 2 _m with two optical fiber cables and carries out large-capacity communication by optical wavelength division multiplexing technology.

Optical transmission device 211₁~ 211_m, 212₁
~ 212_mIs the component that demultiplexes the wavelength-division multiplexed optical carrier.
Wave modulator 221 and optical modulation for modulating the demultiplexed optical carrier
Bowl 222₁~ 222_nAnd combine the output of each optical modulator
And a multiplexer 223 for performing the transmission. Well
Optical transmission device 211₁~ 211_m, 212₁~ 212
_mIs a demultiplexer 224 that demultiplexes the wavelength-multiplexed optical signal.
And an optical receiver 225 for demodulating each of the demultiplexed optical signals
₁~ 225_nAnd a receiving unit having.

The center node 201 is a multi-wavelength light source 231 which generates a plurality of optical carriers of wavelengths 1 to n and outputs it from one optical fiber, and an optical coupler which distributes the output light of the multi-wavelength light source 231 to m + 1. 232. The remote nodes 202 _{1 to} 202 _m include optical couplers 233 _{1 to} 233 _m that divide one input light into two.

Optical coupler 232 of the center node 201
Divides the output of the multi-wavelength light source 231 into m + 1 and outputs m output.
The optical power is the optical transmission device 211 of the center node 201.₁~
211 _mEntered in. The other one of the optical coupler 232
The output light remains unmodulated and is output by another optical fiber transmission line.
To the remote node adjacent to the center node 201.
Sent out. The adjacent remote node is
Even if the remote node geographically closest to Do 201
However, due to the configuration of the optical fiber transmission line, any remote node
It may be a card.

The remote nodes 202 _{1 to} 202 _m receive the unmodulated output light sent from the center node 201 or an adjacent remote node as optical couplers 233 ₁ to 23 3.
The light is split into two by 3 _m , and one output light is transmitted by the optical transmission device 21.
Enter the 2 ₁ -212 _m, the other output light is transmitted to another adjacent remote nodes. The optical coupler may be omitted in the remote node farthest from the center node 201.

With such a configuration, the transmitting unit is
The output of the multi-wavelength light source 231 distributed by the laser 232 is demultiplexed.
The optical carrier after being demultiplexed by the optical modulator 221
22 ₁~ 222_mMultiple independent optical signals modulated by
Wavelength multiplexed into one optical fiber by the multiplexer 223
The wavelength division multiplexed optical signal is transmitted. The receiving unit is
The demultiplexer 224 separates the heavy optical signal into a plurality of signals,
This is the optical receiver 225₁~ 225_nTo receive.

According to this embodiment, in each node,
It is not necessary to arrange a plurality of independent light sources having different wavelengths, and the optical carrier of the same wavelength can be shared for carrying a plurality of independent optical signals. In order to compensate for the attenuation of the optical carrier or the optical signal in the optical transmission device or the optical fiber, one or a plurality of optical amplifiers, for example, erbium-doped optical fiber amplifiers, etc., may be provided at appropriate points in the optical network shown in FIG. May be arranged. For example, the optical amplifier is a multiplexer 223 of the optical transmission devices 211 _{1 to} 211 _m.
In the subsequent stage, the demultiplexer 224 of the optical transmission devices 212 _{1 to} 212 _m
Or the optical couplers 233 _{1 to} 233 _m .

Optical coupler 232 of the center node 201
Can have any distribution ratio. For example, it can be configured by connecting a two-division optical coupler of equal distribution and an m-division optical coupler of equal distribution. Unmodulated output light having an optical power of about ½ is sent to an adjacent remote node, and output light having an optical power of about ½ _m is sent to the optical transmission apparatuses 211 _{1 to} 211 _m .
Further, an optical amplifier may be arranged in the front stage or the rear stage of the optical coupler 232 to compensate the branch loss.

FIG. 3 shows a first example of the configuration of the multi-wavelength light source. The multi-wavelength light source is a laser light source 3 that outputs wavelengths 1 to n.
01 _1-301 and _n, consists multiplexer 302. for multiplexing the output of the laser light source ₃₀₁ 1-301 _n, wavelength 1
n optical carriers are generated and sent out from one optical fiber.

A multi-wavelength light source is disclosed in Japanese Patent Application No. 2000-26.
6125 Specification and Drawings or Japanese Patent Application No. 2000-2
The multi-wavelength light source disclosed in the specification of No. 07494 and the drawings may be used. FIG. 4 shows a second example of the configuration of the multi-wavelength light source. The multi-wavelength light source is a seed light source 4 that outputs wavelengths 1 to n.
01 _{1 to} 401 _n , a multiplexer 402 that multiplexes the outputs of the seed light sources 401 _{1 to} 401 _n, and a multi-wavelength conversion circuit 404 that further generates different wavelengths. The multi-wavelength conversion circuit 404 is configured by connecting a phase modulator and an intensity modulator in series, for example.

The seed light sources 401 _{1 to} 401 _n generate a plurality of side modes to generate a multiple wavelength circuit 404.
Uses the main mode and the side mode as optical carriers, and can output more wavelengths than the seed light sources 401 _{1 to} 401 _n .

When a modulator made of lithium niobate is used for the optical modulators 222 _{1 to} 222 _m ,
Since it has polarization dependence, it causes a problem that it cannot be modulated depending on the polarization state of the input light of the optical modulator. Therefore, the polarization scramble circuit 30 is provided at the output end of the multi-wavelength light source shown in FIG. 3 or the multi-wavelength light source shown in FIG.
By providing 3, 403 and changing the polarization state of the optical carrier faster than the signal rate, the above-mentioned problem can be solved. When an electro-absorption modulator made of a semiconductor material is used for the optical modulators 222 _{1 to} 222 _m , there is no polarization dependence, so the polarization scramble circuits 303 and 40
It is not necessary to connect 3.

In this embodiment, the multi-wavelength light source 231 is used.
Can be composed of two multi-wavelength light sources and an optical switch that selects and outputs one of them. When one of the multi-wavelength light sources fails, the reliability of the node can be improved by switching by the optical switch and using the other multi-wavelength light source.

[Second Embodiment] FIG. 5 shows the first embodiment of the present invention.
2 shows a configuration of an optical network according to the exemplary embodiment. The optical network includes one center node 201 and one remote node 202.
The optical transmission device 211 of 01 is connected to the optical transmission device 212 of the remote node 202 by two optical fiber cables,
Large-capacity communication is performed using optical wavelength multiplexing transmission technology. First
In the above embodiment, m = 1, and it is not necessary to arrange an optical coupler in the remote node 202.

[Third Embodiment] Referring to FIG.
The application to network is explained. Ring-shaped optical network
Detours even if one of the optical fibers is cut
It is a redundant system that can configure a road. the first
In addition, the light according to the first embodiment that is linearly arranged
Figure 6 shows the network arranged in a ring.
It has a different structure. The configuration shown in FIG. 6 corresponds to that of the first embodiment.
The configuration is the same as when m = 3. Multi-wavelength light
The unmodulated output light output from the source 231 is transmitted to each remote.
A single optical fiber transmission line via an optical coupler at a node
So, it is propagating counterclockwise on the ring. In addition,
Internode 201 to three remote nodes 202₁
~ 202 _ThreeThe optical signal sent to the three optical fiber transmission
It propagates counterclockwise on the ring by the road. Furthermore
To three remote nodes 202₁~ 202_ThreeFrom Sen
The optical signal sent to the turn node 201 is the other three optical signals.
It is propagated clockwise on the ring by the fiber transmission line.
It Next, in this configuration,
explain about.

FIG. 7 shows the configuration of an optical network according to the third embodiment of the present invention. Center node 701
Is an optical coupler 732 that distributes unmodulated output light output from the multi-wavelength light source 731 into clockwise, counterclockwise, and in-node on the ring, and optical transmission devices 711 _{1 to} 711.
₃ and ₃ . Remote nodes 702 _{1 to} 702 ₃
Is an optical coupler 7 that distributes the counterclockwise unmodulated output light.
33 _{1 to} 733 ₃ , optical couplers 734 _{1 to} 734 ₃ for distributing clockwise unmodulated output light, and an optical transmission device 712.
And a _{1 to 712 3.}

Optical transmission device 711 of center node 701
And _{1 to 711 3,} and the remote node ₇₀₂ 1 to 702 ₃ of the optical transmission device ₇₁₂ 1 to 712 ₃ are respectively connected on the ring two by the optical fiber transmission line. The optical transmission devices 711 _{1 to} 711 ₃ and 712 _{1 to} 712 ₃ are configured so as to generate optical signals of two systems that are transmitted in opposite directions and select optical signals of two systems that arrive in mutually opposite directions. There is.

FIG. 8 shows the configuration of a remote node according to the third embodiment of the present invention. The optical transmission device 712 of the remote node 702 is arranged in front of the optical coupler 721 that divides the output of the transmission unit into two and sends the output to the center node 701 in the clockwise and counterclockwise directions.
It has an optical switch 722 that selects one of the two systems of optical signals arriving from the center node 701 by clockwise and counterclockwise rotation.

FIG. 9 shows the configuration of a center node according to the third embodiment of the present invention. The configurations of the optical transmission devices 711 _{1 to} 711 ₃ of the center node 701 are the same as the configurations of the optical transmission device 712 of the remote node 702 described above.

With such a configuration, for example, in FIG. 7, it is assumed that communication is performed between the center node 701 and the remote nodes 702 _{1 to} 702 ₃ using the optical fiber transmission line a side. If the optical fiber cable is cut at a point, in the optical transmission device center node 701 and remote node ₇₀₂ 1 to 702 _3, it switches the optical switch 722. In this way
Communication can be continued using the optical fiber transmission line b side.

According to the present embodiment, even when the optical network according to the present invention is applied to a ring network, a detour can be formed and when any one of the ring-shaped optical fibers is cut. Can also be dealt with.

FIG. 10 shows the configuration of an optical transmission device according to the third embodiment of the present invention. A remote node ₇₀₂ 1 to 702 ₃ of the optical transmission apparatus 712 shown in FIG. 8, the optical transmission apparatus ₇₁₁ 1-71 center node 701 shown in FIG. 9
1 ₃ A, by an optical coupler 721 and the optical switch 722 was performed to switch the optical signal with the received optical signal distribution to be transmitted. The optical transmission device may be configured by using two transmitters and two receivers to switch the optical signal distribution to be transmitted and the received optical signal. At this time, each of the nodes, the distributor ₈₀₁ 1 _{~801 n} for distributing the transmission signal input to the optical modulator ₂₂₂ 1 to 222 _n, an optical receiver ₂₂₅ 1-22
5 and a selector ₈₀₂ 1 _{~802 n} to select the output of the _n.

Finally, the cost effectiveness of reducing the number of light source components by using a multi-wavelength light source will be described. Multi-wavelength light source cost ML, individual light source cost SL, multiplexer cost MX, 2 split optical coupler cost CPL, m split optical coupler cost MCPL, optical fiber cost F between adjacent nodes, The conventional optical network shown in FIG. 1 is compared with the optical network according to the present invention shown in FIG. The cost of the components of the optical network according to the present invention is on the left side, the cost of the components of the conventional optical network is on the right side, and ML + MCPL + m × (2MX + CPL + F) <2m × n × SL (1) Is expressed as Here, n is the number of wavelengths and m is the number of remote nodes.

When a multi-wavelength light source that outputs optical carriers of wavelengths 1 to n from one optical fiber is composed of n individual light sources of wavelengths 1 to n and one multiplexer, ML = n × SL + MX (2) and substituting equation (2) into equation (1) gives MCPL + (2m + 1) MX × m (CPL + F) <(2m-1) × n × SL (3). If the number of wavelengths n used for WDM transmission is large,
It can be seen that the effect is great because only the right side of the inequality becomes large. If the ratio of each cost is MCPL: MX: CPL: F: SL = 10: 200: 1: 300: 20 (4), when m = 7, it is effective when the number of wavelengths n is 20 or more. It turns out that is large.

[0041]

As described above, according to the present invention,
In each remote node, it is not necessary to arrange a plurality of independent light sources having different wavelengths, and the number of light source components can be reduced. Further, the wavelength monitoring function / wavelength stabilizing function is not required, and it becomes possible to easily monitor and control the optical transmission device.

Further, since optical carriers of the same wavelength can be shared for carrying a plurality of optical signals, there is an effect that the total number of wavelengths available to all remote nodes is not limited.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional optical network.

FIG. 2 is a configuration diagram showing an optical network according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a first example of a multi-wavelength light source.

FIG. 4 is a configuration diagram showing a second example of a multi-wavelength light source.

FIG. 5 is a configuration diagram showing an optical network according to a second exemplary embodiment of the present invention.

FIG. 6 is a diagram for explaining application to a ring network.

FIG. 7 is a configuration diagram showing an optical network according to a third exemplary embodiment of the present invention.

FIG. 8 is a configuration diagram showing a remote node according to a third exemplary embodiment of the present invention.

FIG. 9 is a configuration diagram showing a center node according to a third exemplary embodiment of the present invention.

FIG. 10 is a configuration diagram showing an optical transmission device according to a third exemplary embodiment of the present invention.

[Explanation of symbols]

101,201,701 Center node 102₁-10_m, 202, 202₁~ 202_m, 7
02,702₁~ 702 _Three    Remote node 111₁~ 111_m, 112₁~ 112_m, 211₁~
211_m, 212₁~ 212_m, 711₁~ 711_Three，
712,712₁~ 712_Three    Optical transmission device 121₁~ 121_n    light source 122₁~ 122_n, 222₁~ 222_n    Light modulator 123, 223, 302, 402 Multiplexer 124,221,224 duplexer 125₁~ 125_n, 225₁~ 225_n    Optical receiver 231,731 Multi-wavelength light source 232, 233₁~ 233_m, 721, 732, 73
3,733₁~ 733_Three, 734, 734₁~ 734_Three
    Optical coupler 301₁~ 301_n    Laser light source 303,403 Polarization scramble circuit 401₁~ 401_n    Seed light source 722,741 Optical switch

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04L 12/44 200 (72) Inventor Katsumi Iwatsuki 2-3-1, Otemachi, Chiyoda-ku, Tokyo Nihonhon Telegraph and Telephone Corporation F term (reference) 5K002 AA07 BA05 BA06 CA14 DA02 DA11 EA32 FA01 5K031 CA15 DA02 DA19 DB12 DB14 5K033 CA17 DA01 DA15 DB02 DB05 DB17 DB22

Claims (6)

[Claims] 1. Communication is performed by connecting at least one optical fiber transmission line to each of a plurality of optical transceivers included in at least one center node and each of optical transceivers included in a plurality of remote nodes. In the optical communication system, the center node distributes the output light from the multi-wavelength light source that generates output light by wavelength-multiplexing a plurality of optical carriers having different wavelengths, and distributes the output light from the multi-wavelength light source. And an optical coupler for sending to an optical connector of an optical fiber transmission line connected to an adjacent remote node and an optical coupler, wherein the remote node outputs the output light sent from the center node or an adjacent remote node. An optical fiber of an optical fiber transmission line that distributes and connects to the remote node adjacent to the optical transceiver of the remote node. And an optical coupler for sending to the optical coupler, each of the optical transceivers inputs the output light from the optical coupler connected to the optical transceiver, and outputs a plurality of optical carriers wavelength-multiplexed to the output light. An optical communication system characterized in that communication is performed by modulating each and sending out to the optical fiber transmission line. 2. An optical transmission / reception unit included in one center node and an optical transmission / reception unit included in one remote node,
In an optical communication system for performing communication by connecting at least one optical fiber transmission line, the center node includes a multi-wavelength light source that generates output light by wavelength-multiplexing a plurality of optical carriers having different wavelengths, and the multi-wavelength light source. An optical coupler for distributing the output light from the optical node to the optical transmitting / receiving unit of the center node and the optical transmitting / receiving unit of the remote node via the optical fiber transmission path, each of the optical transmitting / receiving units Is an optical device for performing communication by inputting the output light from the optical coupler, modulating each of a plurality of optical carriers wavelength-multiplexed with the output light, and transmitting the modulated optical carrier to the optical fiber transmission path. Communications system. 3. The optical transmission / reception unit receives the output light sent from the optical coupler, and demultiplexes it into a plurality of optical carriers; and the plurality of demultiplexers demultiplexed by the demultiplexer. Each of the optical carriers,
A modulator for outputting an optical signal modulated by an electric signal, and each of the optical signals output from the modulator are multiplexed,
The optical communication system according to claim 1 or 2, further comprising: a multiplexer that outputs the optical fiber transmission path. 4. A center node and a plurality of remote nodes are arranged in a ring shape, and each of the plurality of optical transceivers included in the center node and each of the optical transceivers included in the plurality of remote nodes are at least In an optical communication system for performing communication by connecting in a ring shape by two optical fiber transmission lines, the center node includes a multi-wavelength light source that generates output light in which a plurality of optical carriers having different wavelengths are wavelength-multiplexed, An optical coupler that distributes the output light from the wavelength light source and sends the output light to the plurality of optical transceivers of the center node and an optical connector of an optical fiber transmission line connected to two adjacent remote nodes; The node distributes the output light transmitted from the center node or the adjacent remote node, and outputs one output to the adjacent remote node. And two optical couplers for sending to the optical connector of the optical fiber transmission line connected to the optical node, and an optical switch for selecting the other output of the two optical couplers and connecting it to the optical transceiver of the remote node. , Each of the optical transceivers receives the output light from the optical coupler or the optical switch connected to the optical transceiver, and modulates each of a plurality of optical carriers wavelength-multiplexed with the output light, An optical communication system, wherein communication is performed by sending out to the two optical fiber transmission lines. 5. A demultiplexer that receives the output light sent from the optical coupler or the optical switch, and demultiplexes the demultiplexed light into a plurality of optical carriers. A modulator that outputs an optical signal that modulates each of the plurality of demultiplexed optical carriers with an electrical signal, and outputs a wavelength-multiplexed optical signal that combines each of the optical signals output from the modulator A multiplexer, and an optical coupler that distributes the wavelength-multiplexed optical signal output from the multiplexer and sends the optical signal to the two optical fiber transmission lines. An optical switch that selects a wavelength-multiplexed optical signal from two optical fiber transmission lines, a demultiplexer that inputs the wavelength-multiplexed optical signal from the optical switch, and demultiplexes into a plurality of optical signals, and the demultiplexer A receiver for demodulating the demultiplexed optical signal and outputting an output electric signal; An optical communication system according to claim 4, characterized in that it has. 6. The optical transmission / reception unit receives the output light sent from the optical coupler or the optical switch, and demultiplexes it into a plurality of optical carriers, and demultiplexes the demultiplexer. And a modulator for outputting an optical signal obtained by modulating each of the plurality of optical carriers with an input electric signal, and a multiplexer for outputting a transmission signal obtained by multiplexing each of the optical signals output from the modulator. And a distributor for distributing the input electric signal to each of the modulators included in the two transmitters, and a plurality of optical signals for inputting a wavelength-multiplexed optical signal from the optical fiber transmission path. And a receiver for demodulating the optical signal demultiplexed by the demultiplexer and outputting an output electric signal, and each of the two receiving units. And a selector for selecting the output electrical signal to be output. An optical communication system according to claim 4, symptoms.